Goldman: There Will Be as Much Mobile Commerce in 2018 as E-Commerce in 2013

Imagine all the people sitting at their computers buying stuff. Amazon purchases of garbage bags and Canon 5Ds, felted animals on Etsy, Ikea rugs, trampolines from Walmart.com, diapers from Diapers.com, stamps from Stamps.com, etc.

That's e-commerce, and it was a roughly $638 billion business last year.

M-commerce is different: It's the stuff you buy on mobile devices like smartphones and tablets. And we all know it is growing fast. Walmart's head of digital innovation told me that, last year, more than 50 percent of the visits to their website were coming on mobile devices.

Goldman says that by 2018, we'll be seeing roughly as much mobile commerce ($626 billion) as we saw in e-commerce last year. In the shorter term, we're talking a tripling from 2012 to 2014.

I will note that one number—or really, one ratio—seems worth thinking more about.

Goldman's forecast here is that most m-commerce will be tablet-based. While they predict smartphone-based m-commerce growing at $20-$30 billion a year, they see a massive explosion in tablet-based sales.

Another way to logic-check this Goldman forecast is that they see a bigger increase in m-commerce on tablets between 2013 and 2014 alone than the entire smartphone m-commerce market in 2013.

I'm not saying this is wrong, only that it doesn't track with our general experience of what "mobile" has meant. I'm talking traffic here, but what we've seen is tablets, despite relatively low prices and wide availability, experiencing steady growth—while smartphone traffic, on the other hand, has exploded.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.